The present invention deals with a machine for the continuous wet treatment of textile thread formations, as well as a process for operating the machine and a non-touching catch-thread device.
Thread mercerizing machines which are similar in design to piece mercerizing machines are well known. Their production rates are extremely high, producing mercerized goods in the order of 150 tons a week, a production rate which is really too high for many operations. For this reason this machine has found a place in only few plants. This machine is not technically suitable for the market as the quality of the thread mercerized in this machine is unsatisfactory due to the fact that the thread is not (pre-)shrunk or (over-)stretched to any degree. As a result, the fibers on the surface of the thread swell up immediately when dipped into the lye during mercerizing in this machine thereby preventing the swelling of the fibers in the middle of the thread. The tension in the thread which causes the fibers to adhere together and causes the openings for air to close between the fibers is only equal to the magnitude of the shrinkage since the thread is not overstretched by the machine. The increase in the tensile strength of the thread is therefore only 3 to 4%. Furthermore, a surface-mercerized thread which has been mercerized in this machine loses its shine after a few washings because the surface of the thread has also been affected by pressing, pulling and bending. This thread cannot be sold as quality merchandise, at least not in Europe.
There is another type of mercerizing machine in which only a single thread is treated and drawn off cones and is wound up onto cylindrical spool. In this case the thread runs at a speed of about 800 meters per minute over two cylinders, the axes of which can be regulated with respect to each other, so that the thread is placed under tension. However, the resulting merchandise is again unsatisfactory and, therefore the problem of poor quality still exists.
There exists a device that is used to treat thread, in which the various parameters which change and characterize thread cannot be changed singly and independent of each other. If the thread is shrunk with this device so as to keep the degree of mercerization high the tensile strength is correspondingly lowered. Again, it is the tension in the thread which causes the fibers to lie together and the openings for air between the fibers to close, and it is equivalent to the amount of shrinkage, since no machine has overstretched the thread and vice versa. (German DE-OS No. 25 27 450)
The above holds true for the well-known Dixie mercerizing process, as it is described in Great Britain Pat. No. 696 595, for example. None of these known devices employs a multi-roller reel, by way of example, as will be described in detail hereinbelow with reference to the present invention.